Composition of additives, comprising at least one copolymer, one cold-flow improver and one anti-settling additive

ABSTRACT

The present invention relates to a composition of additives, comprising: at least one copolymer having at least one motif of formula (I) and at least one motif of formula (II); at least one cold-flow improver selected from the copolymers of ethylene and unsaturated ester(s); and at least one anti-settling and/or paraffin dispersant additive.

The present invention relates to a composition of particular additives and its use to improve the cold resistance properties of fuels and combustibles during their storage and/or their use at low temperature.

The present invention also relates to fuel and combustible compositions containing such a composition of additives.

PRIOR ART

The fuels or combustibles containing paraffinic compounds, in particular compounds containing n-alkyl, iso-alkyl or n-alkenyl groups such as paraffinic waxes, are known for having deteriorated flow properties at low temperature, typically below 0° C. In particular, it is known that the middle distillates obtained by distillation from crude oils of petroleum origin like diesel fuel or heating oil contain various quantities of n-alkanes or n-paraffins according to their origin. These compounds tend to crystallise at low temperature, plugging hoses, pipes, pumps and filters, for example in the circuits for the fuel of motor vehicles. In winter or in conditions of use of the fuels or combustibles at a temperature lower than 0° C., the phenomenon of crystallisation of these compounds can lead to a reduction in the flow properties of the fuels or combustibles and consequently cause difficulties during their transport, their storage and/or their use. The cold operability of the fuels or combustibles is a very important property, in particular to ensure the cold starting of engines. If the paraffins are crystallised at the bottom of the tank, they can be brought upon starting into the fuel circuit and clog in particular the filters and prefilters positioned upstream of the injection systems (pump and injectors). Likewise, for the storage of heating oils, if paraffins precipitate at the bottom of the tank, they can be transported and block the ducts upstream of the pump and of the system for supplying the boiler (nozzle and filter).

These problems are well known in the field of fuels and combustibles, and numerous additives or mixtures of additives have been proposed and marketed to reduce the size of the crystals of paraffins and/or change their shape and/or delay their formation. The smallest possible crystal size is preferred since it minimises the risks of plugging or clogging of the filters.

The usual agents for improving flow called cold flow improvers or CFIs are in general co- and ter-polymers of ethylene and of vinyl and/or acrylic ester(s), used alone or in a mixture. These cold flow improvers (CFIs), intended to lower the cold filter plugging point (CFPP) and the pour point (PP), inhibit and/or delay the growth of the crystals at low temperature by favouring the dispersion of the crystals of paraffin; these are for example the polymers of ethylene and of vinyl acetate and/or of vinyl propionate (EVA or EVP), also commonly called CFPP additives. This type of additives, very widely known to a person skilled in the art, is systematically added to the conventional middle distillates at refinery output during the winter seasons. These additive-containing distillates are used as a diesel-engine fuel or as a heating fuel. Additional quantities of these additives can be added to the fuels sold in service stations in particular to satisfy winter specifications (“Grand Froid”).

To improve both the CFPP and the pour point of the distillates, it is known to add to these CFI additives additional additives or “boosters” having the function of acting in combination with the CFI additives in such a way as to increase the effectiveness thereof. The prior art abundantly describes such combinations of additives.

For example, mention can be made of the U.S. Pat. No. 3,275,427 describing a middle distillate of a distillation cut between 177 and 400° C. containing an additive consisting of 90 to 10% by weight of a copolymer of ethylene comprising 10 to 30% vinyl acetate units having a molar mass by weight between 1000 and 3000 g·mol⁻¹ and of 10 to 90% by weight of a lauryl polyacrylate and/or of a lauryl polymethacrylate having a molar mass by weight varying from 760 to 100.000 g·mol⁻¹.

The document EP0857776 proposes using alkylphenol-aldehyde resins coming from the condensation of alkylphenol and of aldehyde in association with ethylene/vinyl ester copolymers or terpolymers to improve the fluidity of mineral oils.

The patent application WO 2008/006965 describes the use of a combination of a homopolymer obtained from an olefinic ester of carboxylic acid of 3 to 12 carbon atoms and a fatty alcohol comprising a chain of more than 16 carbon atoms and optionally an olefinic double bond and a cold flow improver (CFI) of the EVA or EVP type to increase the effectiveness of the CFI additives by amplifying their effect on the CFPP.

The patent application WO 2016/128379 describes the use, as a cold flow additive for a fuel or combustible, of a block copolymer comprising:

(i) a block A consisting of a chain of structural units derived from one or more alkyl acrylate or methacrylate α,β-unsaturated monomers,

(ii) a block B consisting of a chain of structural units derived from one or more α,β-unsaturated monomers containing at least one aromatic ring.

This additive is in particular useful as a CFPP booster in association with a cold flow improver (CFI).

Besides the improvement of the flow of the fuel or combustible composition, another goal of the cold resistance additives is to ensure the dispersion of the crystals of paraffins, in such a way as to delay or prevent the settling of such crystals and avoid the formation of a layer rich in paraffins at the bottom of the containers, tanks or storage tanks; these paraffin-dispersing additives are called wax anti-settling additives or WASAs.

Modified alkylphenol-aldehyde resins have been described in the document FR2969620 as an anti-settling additive in combination with a CFPP additive.

Because of the diversification of the sources of fuels and combustibles, there is still a need to find new additives to improve the properties of the fuels or combustibles at low temperature also called cold resistance properties, and in particular their flow properties during their storage and/or their use at low temperature.

This need is particularly important for the fuels or combustibles comprising one or more paraffinic compounds, for example compounds containing n-alkyl, iso-alkyl or n-alkenyl groups having a tendency to crystallise at low temperature.

In particular, the distillates used in the fuels and combustibles increasingly come from refining operations that are more complex than those coming from the direct distillation of the petroleum, and can come in particular from the methods of cracking, hydrocracking, catalytic cracking and from the methods of visbreaking. With the increasing demand for diesel fuels, a refiner tends to introduce into these fuels cuts that are more difficult to use, like the heavier cuts coming from the methods of cracking and of visbreaking that are rich in long-chain paraffins.

Moreover, synthetic distillates coming from the transformation of gases such as those coming from the Fischer-Tropsch process, as well as distillates resulting from the treatment of biomasses of plant or animal origin, in particular like NexBTL and distillates comprising esters of vegetable or animal oils, have appeared on the market, and form a new range of products usable as a base to formulate fuels and/or heating oils. These products also comprise hydrocarbons with long paraffinic chains.

Moreover, the arrival of new crude oils on the market, much richer in paraffins than those commonly refined and for which the filter plugging point of the distillates coming from direct distillation was difficult to improve by conventional filterability additives in the same way as those mentioned above, has been noted.

It has been noted that the cold resistance properties of the distillates obtained by combining old bases and these new sources was difficult to improve by the addition of conventional filterability additives, inter alia because of the significant presence of long-chain paraffins and the complex distribution of paraffins in their composition. In these new combinations of distillates, discontinuous distributions of paraffins, in the presence of which the known filterability additives are not always sufficiently effective, have been noted.

There is therefore a need to adapt the cold resistance additives to these new types of bases for fuels and combustibles, considered to be particularly difficult to process.

The present invention applies to the fuels and combustibles containing not only conventional distillates such as those coming from the direct distillation of crude oils, but also to the bases coming from other sources, such as those described above.

Thus, the goal of the present invention is to propose a new composition of additives that can advantageously be used to improve the cold resistance properties, in particular the cold flow properties of these fuels or combustibles, during their storage and/or their use at low temperature, typically less than 0° C.

The goal of the present invention is moreover to propose a new composition of additives for fuels and combustibles, and concentrates containing such a composition, acting on the cold filter plugging point (CFPP), the pour point (PP), and delaying and/or preventing the settling of crystals of hydrocarbon compounds, in particular of the paraffins.

Finally, another goal of the invention is to propose a fuel or combustible composition having improved cold resistance properties, in particular at temperatures of less than 0° C., preferably less than −5° C.

Object of the Invention

The applicant has now discovered than a composition of particular additives, such as those described below, had unexpected properties for improving the cold resistance of the compositions of fuels and of combustibles, including those that are particularly difficult to process.

An object of the present invention is therefore a composition of additives comprising:

-   -   at least one copolymer comprising:     -   at least one unit having the following formula (I):

in which

R₁ represents a hydrogen atom or a methyl group, X represents —O—CO—, or —CO—O— or —NH—CO— or —CO—NH—, and R₂ represents a C6 to C24 alkyl group; and

-   -   at least one unit having the following formula (II):

in which R represents a C2 to C34 group, comprising at least one nitrogen heterocycle;

-   -   at least one cold flow improver chosen from the copolymers of         ethylene and of unsaturated ester(s);     -   at least one anti-settling additive and/or paraffin dispersant.

Another object of the invention is the use of the composition of additives according to the invention to improve the cold resistance properties of a fuel or combustible composition.

Another object of the invention is a concentrate of additives containing such a composition, as well as a fuel or combustible composition.

Other objects, features, aspects and advantages of the invention will appear even more clearly upon reading the description and the examples that follow.

Hereinafter, and unless otherwise indicated, the limits of a range of values are comprised in this range, in particular in the expressions “between” and “ranging from . . . to . . . ”.

Moreover, the expressions “at least one” and “at least” used in the present description are respectively equivalent to the expressions “one or more” and “greater than or equal”.

Finally, in a manner known per se, a C_(N) compound or group designates a compound or a group containing in its chemical structure N carbon atoms.

DETAILED DESCRIPTION

The Composition of Additives:

The invention implements a composition of additives comprising at least one copolymer comprising at least one unit having the following formula (I):

in which R₁ represents a hydrogen atom or a methyl group, X represents —O—CO—, or —CO—O— or —NH—CO— or —CO—NH—, and R₂ represents a C6 to C24 alkyl group.

The group X of formula (I) is chosen from:

-   -   X=—O—CO—, with it being understood that X is thus bound to the         vinylic carbon by the oxygen atom;     -   X=—CO—O—, with it being understood that X is thus bound to the         vinylic carbon by the carbon atom;     -   X=—NH—CO—, with it being understood that X is thus bound to the         vinylic carbon by the nitrogen atom; and     -   X=—CO—NH—, with it being understood that X is thus bound to the         vinylic carbon by the carbon atom.

According to a first embodiment, the group X of formula (I) is chosen from: —O—CO— and —NH—CO—, with it being understood that the group X=—O—CO— is bound to the vinylic carbon by the oxygen atom and that the group X=—NH—CO— is bound to the vinylic carbon by the nitrogen atom. In this embodiment, the group X of formula (I) is preferably the group —O—CO—.

According to a second embodiment, the group X of formula (I) is chosen from: —CO—O— and —CO—NH—, with it being understood that the group X is bound to the vinylic carbon by the carbon atom. In this embodiment, the group X of formula (I) is preferably the group —CO—O—.

According to a particularly preferred embodiment, the group X is a —CO—O— group, X being bound to the vinylic carbon by the carbon atom.

The group R₂ of formula (I) is a C₆ to C₂₄ alkyl radical. This alkyl radical can be linear or branched, cyclic or acyclic. This alkyl radical can comprise a linear or branched part and a cyclic part.

Advantageously, the group R₂ of formula (I) is a C₈-C₂₄, preferably C₁₀-C₂₂, more preferably C₁₂-C₂₂ linear or branched acyclic alkyl radical. According to a specific embodiment, the group R₂ of formula (I) is a C₁₂-C₁₄ linear or branched acyclic alkyl radical. According to another specific embodiment, the group R₂ of formula (I) is a C₁₈-C₂₂ linear or branched acyclic alkyl radical.

Mention can be made, as non-limiting examples of preferred groups R₂, of the alkyl groups such as octyl, decyl, dodecyl, ethyl-2-hexyl, isooctyl, isodecyl, isododecyl, lauryl, stearyl, octadecyl, behenyl, the C₁₄ alkyl groups.

According to a particularly preferred embodiment, the group X is a —CO—O— group, X being bound to the vinylic carbon by the carbon atom, and the group R₂ is a C₈-C₂₄, preferably C₁₀-C₂₂, more preferably C₁₂-C₂₂ linear or branched acyclic alkyl radical.

The units according to this embodiment correspond to those coming from monomers chosen from the C₈-C₂₄, preferably C₁₀-C₂₂, more preferably C₁₂-C₂₂ alkyl acrylates and methacrylates.

According to a specific embodiment, the group X is a —CO—O— group, X being bound to the vinylic carbon by the carbon atom, and the group R₂ is a C₁₂-C₁₄ linear or branched acyclic alkyl radical. The units according to this embodiment corresponds to those coming from monomers chosen from the C₁₂-C₁₄ alkyl acrylates and methacrylates.

According to another specific embodiment, the group X is a —CO—O— group, X being bound to the vinylic carbon by the carbon atom, and the group R₂ is a C₁₈-C₂₂ linear or branched acyclic alkyl radical. The units according to this embodiment corresponds to those coming from monomers chosen from the C₁₈-C₂₂ alkyl acrylates and methacrylates.

The copolymer used in the present invention also comprises at least one unit having the following formula (II):

in which R represents a C₂ to C₃₄, preferably C₂ to C₁₂, more preferably C₂ to C₆ group, preferably comprising at least one nitrogen heterocycle.

Nitrogen heterocycle designates in a manner known per se a cyclic group comprising carbon atoms and at least one nitrogen atom in the cycle.

The group R can be saturated or unsaturated, monocyclic or polycyclic, and the cycle(s) can be substituted or non-substituted. The substituent(s) possibly present in the cycle(s) can be saturated or unsaturated, and in particular be chosen from the hydrocarbon, oxygen, nitrogen, halogen . . . substituents.

According to a preferred embodiment, the nitrogen heterocycle(s) are chosen from the cycles formed by 5 to 7 atoms among which 1, 2, 3 or 4 atoms are nitrogen atoms, these cycles being saturated or unsaturated, substituted or non-substituted.

As non-limiting examples of nitrogen heterocycles mention can be made of the following cycles: pyrrolidine, pyrroline, pyrrole, pyrazolidine, imidazolidine, pyrazoline, imidazoline, pyrazole, imidazole, triazole, tetrazole, piperidine, pyridine, piperazine, pyridazine, pyrimidine, pyrazine, triazine.

The nitrogen heterocycle(s) can also contain, in addition to the carbon and nitrogen atoms, one or more other heteroatoms such as in particular one or more oxygen atoms, which can be part of the cycle or be attached to it. For example, mention can be made of the following cycles: pyrrolidone, caprolactam.

According to a preferred embodiment, the group R contains at least one nitrogen heterocycle having from one to three nitrogen atoms, more preferably two nitrogen atoms. Preferred groups R are in particular chosen from the following cycles: a substituted or non-substituted imidazole cycle, a substituted or non-substituted triazole cycle, a substituted or non-substituted pyrrolidone cycle.

According to a particularly preferred embodiment, the group R is a substituted or non-substituted imidazole cycle.

According to one embodiment, the units having the formula (II) come from one or more vinyl monomers carrying a group R as described above.

As examples of preferred monomers mention can be made of:

-   -   the 1,2,3 and the 1,2,4 N-vinyltriazoles,     -   N-vinylpyrrolidone,     -   1-vinylimidazole (or N-vinylimidazole), the latter being         particularly preferred.

The copolymer used in the present invention can be cross-linked or not. Preferably, it is not cross-linked.

The copolymer according to the invention advantageously contains from 50 to 99% in moles of units having the formula (I), preferably from 60 to 95% in moles, more preferably from 70 to 90% in moles, and even better from 75 to 85% in moles.

The copolymer according to the invention advantageously contains from 1 to 50% in moles of units having the formula (II), preferably from 5 to 40% in moles, more preferably from 10 to 30% in moles, and even better from 15 to 25% in moles.

Preferably, the copolymer used in the present invention contains only units having the formula (I) and units having the formula (II).

The copolymer used in the present invention is advantageously a statistical copolymer or a block copolymer. According to a particularly preferred embodiment, it is a statistical copolymer.

The copolymer used in the present invention can be obtained by copolymerisation of:

-   -   at least one monomer having the following formula (IA):

in which R₁, X and R₂ are as defined above, the preferred alternatives of R₁, X and R₂ according to the formula (I) described above also being preferred alternatives of the formula (IA), and

-   -   at least one monomer having the following formula (IIA):

in which R is as defined above, the preferred alternatives of R according to the formula (II) described above also being preferred alternatives of the formula (IIA).

When the group X of the monomer having the formula (IA) is the group —O—CO—, with it being understood that the group —O—CO— is bound to the vinylic carbon by the oxygen atom, the monomer having the formula (IA) is, preferably, chosen from the C₈ to C₂₄, preferably C₁₀ to C₂₄, more preferably C₁₂ to C₂₂ vinyl alkyl esters. According to a specific embodiment, the monomer having the formula (IA) is chosen from the C₁₂ to C₁₄ vinyl alkyl esters. According to another specific embodiment, the monomer having the formula (IA) is chosen from the C₁₈ to C₂₂ vinyl alkyl esters. The alkyl radical or alkyl vinyl ester is linear or branched, cyclic or acyclic, preferably acyclic.

Among the alkyl vinyl ester monomers, mention can be made for example of vinyl octanoate, vinyl decanoate, vinyl dodecanoate, vinyl tetradecanoate, vinyl 2-ethylhexanoate.

When the group X of the monomer having the formula (IA) is the group —CO—O—, with it being understood that the group —CO—O— is bound to the vinylic carbon by the carbon atom, the monomer having the formula (IA) is typically chosen from the C₈ to C₂₄, preferably C₁₀ to C₂₄, more preferably C₁₂ to C₂₂ alkyl acrylates and methacrylates. According to a specific embodiment, the monomer having the formula (IA) is chosen from the C₁₂ to C₁₄ alkyl acrylates and methacrylates. According to another specific embodiment, the monomer having the formula (IA) is chosen from the C₁₈ to C₂₂ alkyl acrylates and methacrylates.

Among the alkyl (meth)acrylates capable of being used as monomers in the manufacturing of the copolymer used in the invention, mention can be made of the C₆ to C₂₄ alkyl acrylates and the C₆ to C₂₄ alkyl methacrylates, and in particular, as non-limiting examples: n-octyl acrylate, n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate, n-dodecyl acrylate, n-dodecyl methacrylate, ethyl-2-hexyl acrylate, ethyl-2-hexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isodecyl acrylate, isodecyl methacrylate, lauryl acrylate, stearyl acrylate, octadecyl acrylate, behenyl acrylate, the C₁₂ to C₁₄ alkyl acrylates and the C₁₂ to C₁₄ alkyl methacrylates. It is particularly preferred to use the C₁₂ to C₁₄ alkyl acrylates and the C₁₂ to C₁₄ alkyl methacrylates and also the C₁₈ to C₂₂ alkyl acrylates and the C₁₈ to C₂₂ alkyl methacrylates.

The monomers having the formula (IIA) are vinyl monomers carrying a group R as described above.

According to a particularly preferred embodiment, the group R contains at least one unsaturated nitrogen heterocycle having from one to three nitrogen atoms, more preferably two nitrogen atoms, such as in particular an imidazole cycle, substituted or non-substituted.

As a particularly preferred monomer having the formula (IIA) mention can be made of 1-vinylimidazole (or N-vinylimidazole).

It is understood that it would not be beyond the invention if the copolymer used in the invention was obtained from monomers different than those having the formula (IA) and (IIA) above, insofar as the final copolymer corresponds to a polymer comprising units having the formula (I) and units having the formula (II) as defined above. For example, it would not be beyond the invention if the polymer was obtained by polymerisation of different monomers, followed by a post-functionalisation. For example, the units having the formula (I) can be obtained from acrylic acid, by a transesterification reaction.

The copolymer used in the invention can be prepared via any known polymerisation method. The various polymerisation and cross-linking techniques and conditions are broadly described in the literature and are part of the general knowledge of a person skilled in the art.

In the case of a statistical copolymer, conventional free-radical polymerisation can in particular be used: in general a mixture of the various monomers in a suitable solvent is carried out, and the copolymerisation is initiated via a free-radical polymerisation agent.

In the case of a block copolymer, sequenced and controlled polymerisation can in particular be used. Such a polymerisation is, advantageously, chosen from the controlled free-radical polymerisation; for example, by atom transfer radical polymerisation (ATRP); nitroxide-mediated polymerisation (NMP); the degenerative transfer processes such as iodine transfer radical polymerisation (ITRP) or reversible addition-fragmentation chain transfer (RAFT); the polymerisations derived from ATRP such as the polymerisations using initiators for continuous activator regeneration (ICAR) or using activators regenerated by electron transfer (ARGET).

The copolymer used in the invention has, advantageously, a weight-average molecular weight (M_(w)) between 1,000 and 50,000 g·mol⁻¹, more preferably between 1,000 and 20,000 gmol⁻¹, even more preferably between 3,000 and 15,000 g·mol⁻¹.

The copolymer according to the invention has, advantageously, a number-average molecular weight (Mn) between 1,000 and 50,000 g·mol⁻¹, more preferably between 1,000 and 20,000 g·mol⁻¹, even more preferably between 2,000 and 10,000 g·mol⁻¹.

The number- and weight-average molecular weights are measured by Size Exclusion Chromatography (SEC).

The composition of additives according to the invention can, advantageously, comprise from 0.1 to 30% by weight of a copolymer as described above, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight relative to the total weight of the composition of additives.

The composition of additives according to the invention also comprises at least one cold flow improver (CFI) chosen from the copolymers of ethylene and of unsaturated ester(s).

Preferably, the cold flow improver is chosen from the copolymers of ethylene and of vinyl and/or acrylic ester(s), such as the copolymers ethylene/vinyl acetate (EVA), ethylene/vinyl propionate (EVP), ethylene/vinyl ethanoate (EVE), ethylene/methyl methacrylate (EMMA) and ethylene/alkyl fumarate described, for example, in the documents U.S. Pat. Nos. 3,048,479, 3,627,838, 3,790,359, 3,961,961 and EP261957. Mention can also be made of the terpolymers of ethylene, of vinyl acetate and of another vinyl ester, for example vinyl neodecanoate.

According to a preferred embodiment, the cold flow improver (CFI) is chosen from the copolymers of ethylene and of vinyl ester(s), preferably from the ethylene/vinyl acetate (EVA) copolymers, the ethylene/vinyl propionate (EVP) copolymers and the terpolymers of ethylene, of vinyl acetate and of another vinyl ester; even more preferably the ethylene/vinyl acetate copolymers and their mixtures with a terpolymer of ethylene, of vinyl acetate and of another vinyl ester, in particular such as vinyl neodecanoate.

The composition of additives according to the invention can, advantageously, comprise from 50 to 90% by weight of a cold flow improver (CFI) as described above, preferably from 60 to 90% by weight, more preferably from 70 to 90% by weight relative to the total weight of the composition of additives.

The composition of additives according to the invention also comprises at least one anti-settling additive and/or paraffin dispersant.

The anti-settling additive and/or paraffin dispersant (WASA) can in particular, but not limitingly, be chosen from the group consisting of the (meth)acrylic acid/alkyl (meth)acrylate copolymers amidified by a polyamine, the products of condensation of one or more carboxylic acids with one or more polyamines, the polyamine alkenylsuccinimides, the derivatives of phthalamic acid and of two-chain fatty amine; the optionally grafted alkylphenol resins, the modified alkylphenol-aldehyde resins. Examples of such additives are given in the following documents: EP261959, EP593331, EP674689, EP327423, EP512889, EP832172; US2005/0223631; U.S. Pat. No. 5,998,530; WO93/14178; WO2012/085865.

The anti-settling additive and/or paraffin dispersant (WASA) particularly preferred is chosen from the alkylphenol resins and the alkylphenol resins grafted for example by functional groups such as polyamines.

The composition of additives according to the invention can, advantageously, comprise from 1 to 50% by weight of anti-settling additive and/or paraffin dispersant as described above, preferably from 2 to 30% by weight, more preferably from 5 to 20% by weight relative to the total weight of the composition of additives.

The composition of additives according to the invention can also comprise one or more other additives routinely used in fuels or combustibles, different from the copolymer, the cold-resistance additives, and the anti-settling additive described above.

The composition of additives can, typically, comprise one or more other additives chosen from the detergents, the anti-corrosion agents, the dispersants, the demulsifiers, the biocides, the reodorants, the cetane improvers, the friction modifiers, the lubricity additives, the combustion aids (catalytic promoters of combustion and of soot), the anti-wear agents and/or the agents modifying the conductivity.

Among these additives, mention can be made in particular of:

a) the cetane improvers, in particular (but not limitingly) chosen from the alkyl nitrates, preferably 2-ethyl hexyl nitrate, the aryl peroxides, preferably benzyl peroxide, and the alkyl peroxides, preferably tert-butyl peroxide;

b) the anti-foaming additives, in particular (but not limitingly) chosen from the polysiloxanes, the oxyalkylated polysiloxanes, and the amides of fatty acids coming from vegetable or animal oils. Examples of such additives are given in EP861882, EP663000, EP736590;

c) the detergent and/or anti-corrosion additives, in particular (but not limitingly) chosen from the group consisting of the amines, the succinimides, the alkenylsuccinimides, the polyalkylamines, the polyalkyl polyamines, polyetheramines, the quaternary ammonium salts and the derivatives of triazole; examples of such additives are given in the following documents: EP0938535, US2012/0010112 and WO2012/004300. The block copolymers formed from at least a polar unit and an apolar unit, for example such as those described in the patent application FR 1761700 in the name of the applicant can also advantageously be used;

d) the lubricity additives or anti-wear agents, in particular (but not limitingly) chosen from the group consisting of the fatty acids and their ester or amide derivatives, in particular glycerol monooleate, and the derivatives of mono- and polycyclic carboxylic acids. Examples of such additives are given in the following documents: EP680506, EP860494, WO98/04656, EP915944, FR2772783, FR2772784.

Use

Another object of the present invention is the use, to improve the cold resistance properties of a fuel or combustible composition, of the composition of additives according to the invention.

Said fuel or combustible composition can be a composition chosen from the diesel fuels, the biodiesels, the diesel fuels of the B_(x) type containing x % (v/v) of esters of vegetable or animal oils or of fatty acids, the hydrogenated vegetable oils, and the fuel oils such as the heating oils, x being a number strictly greater than 0 and less than or equal to 100.

The fuel or combustible composition is as described below and advantageously comprises at least one cut of hydrocarbons coming from one or more sources chosen from the group consisting of the mineral sources, preferably petroleum, the animal, plant and synthetic sources.

Advantageously, said composition of additives is used to improve the flow properties at low temperature of the fuel or of the combustible during its storage and/or its use at low temperature, by lowering its cold filter plugging point (or CFPP, measured according to the standard NF EN 116) and/or its pour point (or PP, measured according to the standard ASTM D 7346) and/or by delaying or by preventing the settling of crystals, and preferably by lowering its cold filter plugging point (or CFPP, measured according to the standard NF EN 116).

The composition of additives according to the invention can be used to delay or prevent the settling of the crystals of paraffins and more particularly of n-alkanes, preferably the n-alkanes containing at least 12 carbon atoms, more preferably at least 20 carbon atoms.

Concentrate of Additives:

Another object of the present invention is a concentrate of additives comprising the composition of additives according to the invention, in a mixture with an organic liquid. The organic liquid is advantageously inert with respect to the components of the composition of additives, and miscible with the fuels or combustibles, in particular those coming from one or more sources chosen from the group consisting of the mineral, preferably petroleum, animal, plant and synthetic sources.

The organic liquid is preferably chosen from the aromatic hydrocarbon solvents such as the solvent marketed under the name “Solvesso 150”, the alcohols, the ethers and other oxygenated compounds, and the paraffinic solvents such as hexane, pentane or the isoparaffins, alone or in a mixture.

Fuel or Combustible Composition:

The invention also relates to a fuel or combustible composition, comprising:

(1) at least one cut of hydrocarbons coming from one or more sources chosen from the group consisting of the mineral, animal, plant and synthetic sources, and

(2) at least one composition of additives according to the invention.

The mineral sources are preferably petroleum.

The fuel or combustible composition according to the invention advantageously comprises the copolymer(s) in a concentration of at least 0.0001% by weight, relative to the total weight of the fuel or combustible composition. Preferably, the concentration of copolymer(s) ranges from 0.0001 to 0.01% by weight, more preferably from 0.0002 to 0.005% by weight relative to the total weight of the fuel or combustible composition.

The fuel or combustible composition according to the invention advantageously comprises the cold flow improver(s) in a concentration ranging from 0.0005 to 0.2% by weight, preferably from 0.001 to 0.1% by weight, more preferably from 0.0015 to 0.05% by weight relative to the total weight of the fuel or combustible composition.

The fuel or combustible composition according to the invention advantageously comprises the anti-settling additive and/or paraffin dispersant(s) in a concentration ranging from 0.0001 to 0.1% by weight, preferably from 0.0005 to 0.05% by weight, more preferably from 0.001 to 0.02% by weight, relative to the total weight of the fuel or combustible composition.

The fuels or combustibles can be chosen from the liquid hydrocarbon fuels or combustibles, alone or in a mixture. The liquid hydrocarbon fuels or combustibles comprise in particular middle distillates having a boiling temperature between 100 and 500° C. These distillates can for example be chosen from the distillates obtained by direct distillation of crude hydrocarbons, the vacuum distillates, the hydrotreated distillates, the distillates coming from the catalytic cracking and/or from the hydrocracking of vacuum distillates, the distillates resulting from conversion methods of the ARDS type (by atmospheric residue desulphurisation) and/or from visbreaking, the distillates coming from the use of the Fischer-Tropsch cuts, the distillates resulting from the BTL (biomass to liquid) conversion of plant and/or animal biomass, taken alone or in combination, and/or the biodiesels of animal and/or plant origin and/or the oils and/or esters of vegetable and/or animal oils.

The concentration of sulphur in the fuels or combustibles is, preferably, less than 5,000 ppm, more preferably less than 500 ppm, and even more preferably less than 50 ppm, or even less than 10 ppm, and advantageously without sulphur.

The fuel or combustible is, preferably, chosen from the diesel fuels, the biodiesels, the diesel fuels of the Bx type and the fuel oils, preferably heating oil (HHO).

Diesel fuel of the Bx type for a diesel engine (compression engine) means a diesel fuel that contains x % (v/v) of esters of vegetable or animal oils (including used cooking oils) transformed by a chemical method called transesterification reacting this oil with an alcohol in order to obtain fatty acid esters (FAE). With methanol and ethanol, fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE) are obtained, respectively. The letter “B” followed by a number indicates the percentage of FAE contained in the diesel fuel, x being a number strictly greater than 0 and less than or equal to 100. Thus, a B₉₉ contains 99% FAE and 1% middle distillates of fossil origin, B₂₀, 20% FAE and 80% middle distillates of fossil origin, etc. A distinction is thus made between the diesel fuels of the B₀ type which do not contain oxygenated compounds, diesel fuels of the Bx type which contain x % (v/v) of esters of vegetable or animal oils or of fatty acids, most often methyl esters (VOME or FAME). When the FAE is used alone in the engines, the fuel is designated by the term B100.

The fuel or combustible can also contain hydrogenated vegetable oils, known to a person skilled in the art by the name HVO or HDRD (from “hydrogenation-derived renewable diesel”).

According to a specific development, the fuel or combustible is chosen from the diesel fuels, the biodiesels and the diesel fuels of the B_(x) type, the hydrogenated vegetable oils (HVOs), and the mixtures thereof.

The fuel or combustible composition can also contain one or more additional additives, different than the copolymers, the cold flow improver and the anti-settling additive described above. Such additives can be in particular chosen from the detergents, the anti-corrosion agents, the dispersants, the demulsifiers, the anti-foaming agents, the biocides, the reodorants, the cetane improvers, the friction modifiers, the lubricity additives, the combustion aids (catalytic promoters of combustion and of soot), the anti-wear agents and/or the agents modifying the conductivity.

These additional additives can be in general present in a quantity ranging from 0.005 to 0.1% by weight, relative to the total weight of the fuel or combustible composition (each).

Another object of the invention is a method for improving the cold resistance properties of a fuel or combustible composition involving adding a composition of additives as described above.

The examples below are given for purposes of illustrating the invention, and should not be interpreted in such a way as to limit the scope thereof.

EXAMPLES Example 1: Synthesis of Various Polymers

The various polymers were synthesised by free-radical polymerisation in solution. In a typicxal example, the monomers were solubilised in a solvent chosen from toluene or dioxane, and the transfer agent was added to the mixture. The system was degassed under a flow of nitrogen for 40 minutes and then heated until 70° C. was reached. Once at this temperature, the initiator was added to start the polymerisation. The reaction was left for 6 h. The system was then opened to air and left to cool until the ambient temperature was reached. The polymer formed was recovered by drying under vacuum.

The polymer recovered was characterised by NMR spectroscopy and gas chromatography (GC) in order to determine the composition and the molar mass of the copolymer, respectively.

The characteristics of the polymers synthesised according to the operating mode above are brought together in table I below:

TABLE I Monomer Monomer Type of having the having the M_(W) M_(n) polymer formula (I) formula (II) (g · mol⁻¹) (g · mol⁻¹) Homo- C₁₂/C₁₄ alkyl —  7750 4920 polymer acrylate Statistical C₁₂/C₁₄ alkyl N-vinylimidazole  8100 5700 copolymer 1 acrylate 20% in moles 80% in moles Statistical C₁₂/C₁₄ alkyl N-vinylimidazole 10230 6220 copolymer 2 acrylate 10% in moles 90% in moles

Example 2: Evaluation of the Cold Resistance Performance

A composition G of fuel of the type diesel fuel that is particularly difficult to process, and the characteristics of which are described in detail in table II below:

TABLE II Characteristic Method Value Density at 15° C. ISO 12185 836.8 kg/m³ Cloud point (CP)° EN 23015  −9° C. Cold filter plugging point (CFPP) EN 116 −11° C. Pour point (PP) ASTM D 7346 −15° C. Concentration of paraffins 18.8% by weight Concentration of C16+ n-paraffins 8.51% by weight D86 Distillation profile ISO 3405 Initial point 172° C. Point at 5% vol. 194° C. Point at 10% vol. 203° C. Point at 20% vol. 219° C. Point at 30% vol. 234° C. Point at 40% vol. 250° C. Point at 50% vol. 263° C. Point at 60% vol. 276° C. Point at 70% vol. 290° C. Point at 80% vol. 307° C. Point at 90% vol. 327° C. Point at 95% vol. 346° C. Final point 363° C.

was added with various ingredients.

In particular, two compositions G1 and G2 were prepared.

The composition G1 comprises:

-   -   the additive MDFI A;     -   the additive WASA 1.

The composition G2 comprises:

-   -   the additive MDFI A;     -   the additive WASA 2.

The compositions of the additives are reported in table III below, the concentrations indicated being in percentage by weight relative to the total weight of the additive:

TABLE III Additive MDFI A WASA 1 WASA 2 Solvesso 150 solvent 28 28 28 Ethylene/vinyl acetate 61 20 20 copolymer Ethylene/vinyl acetate/2- 10 — — ethylhexyl acrylate terpolymer Homopolymer as defined in — 10 — example 1 statistical copolymer 1 — — 10 alkylphenol resin grafted with — 32 32 a tallow triamine alpha-olefin/stearyl acrylate/ — 10 10 maleic anhydride amidified with a tallow amine terpolymer

Thus, the composition G1 comprises a comparative composition of additives. The composition G1 is thus a comparative composition. The composition G2 comprises a composition of additives according to the invention. The composition G2 is thus a composition according to the invention.

For the composition G1, 170 ppm of WASA 1 additive were added. Two concentrations of MDFI A additive were tested at 100 and 150 ppm.

For the composition G2, 170 ppm of WASA 2 additive were added. Two concentrations of MDFI A additive were tested at 100 and 150 ppm.

The performance of the compositions of additives was tested, by evaluating their aptitude to lower the cold filter plugging point (CFPP) of the additive-containing compositions of diesel fuel G1 and G2.

The results obtained are presented in the single drawing. The CFPPs of the compositions G1 and G2 were measured in accordance with the standard EN 116.

The drawing presents the CFPP results obtained by adding each of the additives defined above, according to the concentration of MDFI A additive, the concentration of WASA 1, WASA 2 additive, respectively, being constant (170 ppm).

The curve A corresponds to the results relating to the comparative composition G1. The curve B corresponds to the results relating to the composition G2 according to the invention.

The CFPP target to be reached is set to −28° C., as has been shown in the single drawing (dotted line).

The drawing thus shows that the composition of additives according to the invention allows to reach the CFPP target of −28° C. with a concentration of MDFI A additive of only 100 ppm. This same CFPP of −28° C. is reached with the comparative composition of additives with a concentration greater by 50%, i.e. 150 ppm.

Thus, the use of the composition of additives according to the invention allows to reduce by 33% the treatment concentration, with respect to the comparative composition. Moreover, with an identical treatment concentration, the composition of additives according to the invention allows to obtain better cold resistance performance.

Example 3: Evaluation of the Cold Resistance Performance

A composition G′ of fuel of the type diesel fuel that is particularly difficult to process, and the characteristics of which are described in detail in table IV below:

TABLE IV Characteristic Method Value Density at 15° C. ISO 12185 831.1 kg/m³ Cloud point (CP)° EN 23015    −6° C. ? Cold filter plugging point (CFPP) EN 116  −6° C. Pour point (PP) ASTM D 7346 −12° C. Concentration of paraffins 13% by weight Concentration of C16+ n-paraffins  6% by weight D86 Distillation profile ISO 3405 Point initial 167° C. Point at 5% vol. 192° C. Point at 10% vol. 205° C. Point at 20% vol. 225° C. Point at 30% vol. 243° C. Point at 40% vol. 260° C. Point at 50% vol. 276° C. Point at 60% vol. 291° C. Point at 70% vol. 305° C. Point at 80% vol. 319° C. Point at 90% vol. 335° C. Point at 95% vol. 349° C. Final point 355° C.

was added with various ingredients.

In particular, three compositions G′1, G′2 and G′3 were prepared.

The composition G′1 comprises:

the additive MDFI B, in Solvesso 150 solvent (28% by weight relative to the weight of the additive), marketed by the company Total Additifs Carburants Spéciaux, which comprises 65% by weight of an ethylene/vinyl acetate copolymer (EVA), and 7% by weight of an alpha-olefin/stearyl acrylate/maleic anhydride amidified with a tallow amine terpolymer.

The composition G′2 comprises:

-   -   the additive MDFI B as described above;     -   the additive WASA 1 as described in example 2.

The composition G′3 comprises:

-   -   the additive MDFI B as described above;     -   the additive WASA 2 as described in example 2.

Thus, the compositions G′1 and G′2 comprise a comparative composition of additives. The compositions G′1 and G′2 are thus comparative compositions. The composition G′3 comprises a composition of additives according to the invention. The composition G′3 is thus a composition according to the invention.

For each of the compositions G′1, G′2 and G′3, two concentrations of MDFI B additive were tested: 400 and 600 ppm.

For the composition G′2, 200 ppm of WASA 1 additive were added.

For the composition G′3, 200 ppm of WASA 2 additive were added.

The performance of the compositions of additives was tested, by evaluating their aptitude to lower the cold filter plugging point (CFPP) of the additive-containing compositions of diesel fuel G′1, G′2 and G′3. The CFPPs of the compositions G′1, G′2 and G′3 were measured in accordance with the standard EN 116.

The results obtained are presented in table V below:

TABLE V CFPP (° C.) CFPP (° C.) CFPP (° C.) Compositions G'1 G'2 G'3 G'1 MDFI B 400 ppm −18° C. — — G'1 MDFI B 600 ppm −25° C. — — G'2 MDFI B 400 ppm — −20° C. — G'2 MDFI B 600 ppm — −23° C. — G'3 MDFI B 400 ppm — — −24° C. G'3 MDFI B 600 ppm — — −27° C.

The results clearly show that the composition of additives according to the invention leads to a significant lowering of the CFPP. 

1. A composition of additives comprising: at least one copolymer comprising: at least one unit having the following formula (I):

in which R₁ represents a hydrogen atom or a methyl group, X represents —O—CO—, or —CO—O— or —NH—CO— or —CO—NH—, and R₂ represents a C₆ to C₂₄ alkyl group; and at least one unit having the following formula (II):

in which R represents a C₂ to C₃₄ group, comprising at least one nitrogen heterocycle; at least one cold flow improver chosen from the copolymers of ethylene and of unsaturated ester(s); at least one anti-settling additive and/or paraffin dispersant.
 2. The composition according to claim 1, characterised in that the group R contains at least one nitrogen heterocycle having from one to three nitrogen atoms, more preferably two nitrogen atoms, even more preferably the group R is chosen from the following cycles: a substituted or non-substituted imidazole cycle, a substituted or non-substituted triazole cycle, a substituted or non-substituted pyrrolidone cycle; and even more preferably the group R is a substituted or non-substituted imidazole cycle.
 3. The composition according to claim 1, characterised in that said copolymer contains only units having the formula (I) and units having the formula (II).
 4. The composition according to claim 1, characterised in that said copolymer is a statistical copolymer, or a block copolymer, and preferably said copolymer is a statistical copolymer.
 5. The composition according to claim 1, characterised in that it comprises from 0.1 to 30% by weight of said copolymer, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight relative to the total weight of the composition of additives.
 6. The composition according to claim 1, characterised in that it comprises from 50 to 90% by weight of said cold flow improver, preferably from 60 to 90% by weight, more preferably from 70 to 90% by weight relative to the total weight of the composition of additives.
 7. The composition according to claim 1, characterised in that it comprises from 1 to 50% by weight of said anti-settling additive and/or of said paraffin dispersant, preferably from 2 to 30% by weight, more preferably from 5 to 20% by weight relative to the total weight of the composition of additives.
 8. The composition according to claim 1, characterised in that the cold flow improver is chosen from the copolymers of ethylene and of vinyl and/or acrylic ester(s), preferably from the copolymers of ethylene and of vinyl ester(s), more preferably from the ethylene/vinyl acetate copolymers, the ethylene/vinyl propionate copolymers and the terpolymers of ethylene, of vinyl acetate and of another vinyl ester, even more preferably the ethylene/vinyl acetate copolymers and their mixtures with a terpolymer of ethylene, of vinyl acetate and of another vinyl ester, in particular such as vinyl neodecanoate.
 9. The composition according to claim 1, characterised in that the anti-settling additive is chosen from the group consisting of the (meth)acrylic acid/alkyl (meth)acrylate copolymers amidified by a polyamine, the polyamine alkenylsuccinimides, the derivatives of phthalamic acid and of two-chain fatty amine, the products of condensation of one or more carboxylic acids with one or more polyamines, modified alkylphenol-aldehyde resins and optionally grafted alkylphenol resins, preferably the alkylphenol resins and the grafted alkylphenol resins.
 10. A use, to improve the cold resistance properties of a fuel or combustible composition, of the composition of additives as defined in claim
 1. 11. The use according to claim 10, characterised in that the fuel or combustible composition is chosen from the diesel fuels, the biodiesels, the diesel fuels of the B_(x) type containing x % (v/v) of esters of vegetable or animal oils or of fatty acids, the hydrogenated vegetable oils, and the fuel oils such as the heating oils.
 12. The use according to claim 10 to lower the cold filter plugging point measured according to the standard NF EN 116 and/or the pour point measured according to the standard ASTM D 7346, and/or to delay or prevent the settling of crystals, and preferably to lower the cold filter plugging point measured according to the standard NF EN
 116. 13. A concentrate of additives comprising a composition of additives as defined in claim 1, in a mixture with an organic liquid.
 14. A fuel or combustible composition, comprising: (1) at least one cut of hydrocarbons coming from one or more sources chosen from the group consisting of the mineral, animal, plant and synthetic sources, and (2) at least one composition of additives as defined in claim
 1. 15. A fuel according to claim 14, characterised in that it contains the copolymer(s) in a concentration of at least 0.0001% by weight, preferably in a concentration ranging from 0.0001 to 0.01% by weight, more preferably from 0.0002 to 0.005% by weight relative to the total weight of the composition. 